The Qualm is a giant mass of tentacles and leaves with hundreds of mouth-like pods lined with teeth. It is about 1/8 of the size of Earth's moon, and it travels through space looking for nutrient rich planets that it can suck dry.
A basin type hole in the middle of the plains. Once every so many years the rains come very hard and flood this place. Maybe that is where the tribes congregate for their tribal meetings.